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Vitamin B12 (Cobalamin) with Mass Concentration Measurement

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of vitamin B12 in your blood, an essential nutrient needed for nerve function and red blood cell production.

Quick summary

["Low levels may indicate deficiencies or health conditions requiring medical attention."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
49077-1
Short code
FLUBV IgG CSF-mCnc
Synonyms
FLUBV IgG CSF-mCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to check for vitamin B12 deficiency, which can cause symptoms like fatigue, numbness, or weakness. It’s also used to monitor conditions like pernicious anemia, certain gastrointestinal diseases, or after treatments that may affect vitamin absorption.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the draw if your lab uses a specific protocol. Bring any medications you’re taking to discuss with your provider.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel slight discomfort, but it should only last a few minutes. The blood sample is then sent to the lab for analysis.

What Does the Test Result Mean?

Results are compared to standard reference ranges, but your provider will interpret them in the context of your overall health and symptoms. Very low levels may need immediate attention, while mild deficiencies may require lifestyle or dietary changes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin B12 Level

Frequently asked questions

What Are My Next Steps If My Test Result Is Abnormal?
If your vitamin B12 level is low, your doctor may recommend dietary adjustments, supplements, or further testing to identify the cause. Follow-up may include checking folate levels or reviewing medications that could interfere with absorption.
How Often Should I Get This Test?
Your provider will determine frequency based on your health history, symptoms, and risk factors. For example, people with at-risk conditions (like celiac disease or chronic gastritis) may need more frequent monitoring.
Can I Take Vitamin B12 Supplements Without Checking My Levels First?
No. Taking supplements without medical guidance can mask symptoms or lead to overuse. Always consult your doctor before starting supplements, especially if you have conditions like kidney disease or certain genetic disorders.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy